Apparatus adapted to opto-electrically monitor the output of a prime mover to provide signals which are fed back to the input and thereby provide control of the prime mover

ABSTRACT

Apparatus is disclosed for obtaining torque and angular velocity of a load transmitting shaft of a prime mover to provide control functions that can be fed back to the operational controls of said prime mover thereby to monitor and control the operating characteristics thereof. The apparatus is described primarily in connection with the preferred embodiment thereof in which torque and rpm data from the drive shaft of an automobile are used to derive further data in the way of electric signals which in turn are fed back to control the automobile output and provide, among other things, pollution and/or efficiency control for the automobile. The torque values are obtained using a light modulation scheme whereby the modulated light provides electric signals from which the torque information is derived.

United States Patent 1191 Pratt, Jr. et al. Aug. 5, 1975 l l APPARATUSADAPTED T0 3.194.065 7/1965 Wilson 73/136 A OPTO-ELECTRICALLY MONITORTHE w es 3.616.687 1 1/197] Wignall .1 73/l36 A BACK To T INPUT ANDTHEREBY Primary E.\'aminer-Charles .l. Myhre PROVIDE ('ONTROL OF THEPRIME Assistant Examiner-Joseph Cangelosi MOVER Armrm'y. Agent. orFirm-Arthur A. Smith. Jr.: [75] Inventors: George W. Pratt, .In,Wayland. Robert Shaw; Marti" Santa Muss; Paul G. McMullin, Pcekskill,NY. [57] ABSTRACT l l Assigneei Massachusens st l 0f Apparatus isdisclosed for obtaining torque and angugyl Cambridge. MZISS- Iarvelocity of a load transmitting shaft of a prime '22} Filed: 0c. I0.1973 mover to provide control functions that can be fed back to theoperatlonal controls of said prime mover I pp 1l86 thereby to monitorand control the operating charac- Rela'ed U 8 Application Data teristicsthereof. The apparatus is described primarily (n C I I f S, N M 486 M 10in connection with the preferred embodiment thereof l l sf i z 'j 0 inwhich torque and rpm data from the drive shaft of an automobile are usedto derive further data in the way of electric signals which in turn arefed back to control the automobile output and provide, among [5 i hl23/l4'6 73/66 other things, pollution and/or efficiency control for e oa c the automobile. The torque values are obtained using a lightmodulation scheme whereby the modulated Reerences Cited light provideselectric signals from which the torque UNITED STATES PATENTS informationis derived. 2.9111002 4/1901 Feldcr .1 73/130 A 3.040.003 8/1962 FeldcrH 73/130 A 21 Clam, 31 Drawing Figures OP ERATING 'NTERNAL PARAMETERSE'B EF 30 320 m4 1 I 1 "Si I CONTROL t SERVO SERVO SERVO l l fill?DEVICE DEVICE DEVICE 1 1:9 1 ,5 I J RPM 4 l MEASURlgJG I I MEAN IMULTIPLIER DRWE l I 19' 1 SHAFT l I I TORQUE 7 l9 MEASURING MEANS I 6 T0omveu l WHEELS 1 l l PAIENIED AUG 1975 SHEET I I I I I I I l i I I I I II 4 N N L ES 3 ANHWE ET q I I VF RF. EM 2 IS NME Ds o l T C a 1 I I 5 6s G m 05 M EN 2 II S s U m m n fJwN ll v PuA RSA RA EE RSE OAE FDJR SD AM TEM OM M M E m V EE r\ 0 so 8 3 I W 0F. 9 I vm 2 m R I am Mr. U .r U M0 2 3 LN I m I... I TUE I m C n/ FIG.

FIG. 2

us T I02 sou ce FIG. 4

INVENTOR GEORGE w, PRATT, JR. PAUL s. McM

FIG.

UL IN d2.

ATTORNEY T T Q 20 SCHMITT TRlGGER LOGIC GATE 57 l l I I l L L 4. r-27TRIGG R 56 TIME AVERAGER 7-. I F 1 l8 MONOSTABLE Tl M E R I I I I PULSEMULTIPLIER GENERATOR AVERAGE l HORSEPOWER A" H wA-fl OUT L l 9' T0FUNCTION FUNCTION GENERATOR GENERATOR FIG. 5A

LOGIC \\STATE ELEMENT 00 0| l0 1| AND J OR J J J NAND J J J NOR FIG. IO

INVENTORZ GEORGE W. PRATT, JR. PAUL G. McMULLlN AT TORNEY PATENTEDAUBSIMS SHEET I/ IF 7 2 7 7 5 w R R Q 8 E II A EA L MR W l nw u w A U W M Tmm m M Hm CR ST R l E O A 5 5 R 2 vll T J A A E m m Afim ME/ m: 2 o a MFIG. 5B

FIG.

o PHOTODIODE OR LIGHT PIPE LEADING TO PHOTOCELL BOUNDARY 706 LOCATED AT697 7712 i7 r x AT TIME I A V CHANNEL A (SOURCE OF v IN MOTION OF Z FIG.5c) LTIME Z777 BAND Z CHANNEL B (SOURCE OF v IN To 7 FIG. 50) 704 706 b70l 705 \70? MOTION OF A BAND 7,? TIME 1 AI o I BOUNDARY 706 AT LATERTIME 1; 697 I LOCATED AT x I o FIG. 50

I +AI TIME TO FIG. 5E

Z ALWAYS STARTS ZERO FROM A,e BVB l x I 1 1 I ZERO FROM c-o ALWAYS STOPSVC c o FIGI5G INvENToRs= 2 GEORGE w. PRATT, JR.

FIG. 5F PAU G. McMuLL N BY f- ATTORNEY PATENTED NIB 51975 SHEET 6CHANNEL A IOOYW W z//r ,4 I A j\/ 7 CHANNE L B CHANNEL C CHANNEL D 38 IOUTPUT 0F I SCHMITT TIME i i t J TRIGGER 22 4 3 FIG.6D 2 Q OUTPUT 0F 39I SCHMITT J TRIGGER 23 TIME I I I 40 FIG.6E I

r' I OUTPUT OF 2 I AND GATE *2 I-- ''I I AT 26 TIME I FIG. 6F I';

I OUTPUT OF I SCHMITT TRIGGER 22' TIME I I J *4 s 3 I 1 t. I.

FIG. 66

INVENTORS GEORGE W. PRATT,JR. PAUL G, McMULLlN ATTORNEY PAIENIEUMJB51915 CONTROL FUNCTION GENERATOR ADDER I I I SERVO DEVICE OPERATINGPARAMETERS INVENTORS GEORGE W PRATT, JR. PAUL GI MC MULLIN BYx ATTORNEYPATENTED AUG 51975 SLZET INVE NTORS GEORGE W. PRATT, JR.

PAUL G. MC MULLIN ATTORNEY PATENTEDAUG 5197s 3, 897, 766

sum 10 W F )3? ama? :QUDIM 0 Rggw ZED? [MGM i LF' gum Wfiflm NVENTORS'.

GEORGE Wv PRATT, JR

PAUL s. MCMULLIN TTORNEY PATENTEU 5W5 $4.897, 766

SHEET 1 1 A B C D E F FIG. I6

230 A-B PULSE TRAIN l /26 L PULSE WIDTH LOGIC GATE MODULATED SIGNAL ORCONTAINING L OTHER TORQUE a MECHANICAL 231 SlGNAL =r+-| C-D PULSE TRAINI .l I 27 LOGIC GATE P OR OTHER TIME AVERAGER 252 f m EF PULSE TRAINPULSE WIDTH MOOULATED SIGNAL CONTAINING ONLY MECHANICAL SIGNAL= M TIMEAVERAGER 2|? I v 4 l8 SUBTRACT (T+m ii FIG, I7

INVENTORS GEORGE W PRATT, JR.

PAUL 6 Mc MULLIN ATTORNEY PAIENIEB 5% R. 897', 766

SHEET 12 RPM AND 1' AND 3% d FF MEAsURING MEASURING MEANS MEANS l RPM d?(RPM) T 320A CONTROL FUNCTION GENERATOR l 2 l 0 0 O 0 sERvo sERvo sERvosERvo 0 0 a A 29L/ DEVICE 3o' DEVICE 3 DEVICE DEVICE 32' I F V I SPARKFUEL TO FUEL S IESE ADVANCE AIR RATIO SUPPLY DEV'CES 1 -1 V U d F/G. l8

APPARATUS ADAPTED TO OPTO-ELECTRICALLY MONITOR THE OUTPUT OF A PRIMEMOVER TO PROVIDE SIGNALS WHICH ARE FED BACK TO THE INPUT AND THEREBYPROVIDE CONTROL OF THE PRIME MOVER This is a continuation-in-part ofapplication Ser. No. l4l,486 filed on May 10, 1971, now abandoned.

The present invention relates to control apparatus for controlling theoperating characteristics of a prime mover and, in particular, toapparatus wherein light modulation is used to provide signals indicativeof the output of the prime mover, which signals can be fed back tocontrol the prime mover.

Prior art of interest in connection with the present invention isdisclosed in US. Patent No. 2,586,540 (Holden); No. 3,495,452 (Johnson,.Ir., et al.)', No. 2,136,223 (Thomas); No. 2,3l3,923 (Chubb): No.2,947,]68 (Yang); N0. 3,130,58! (Schulman); No. 2,402,7[9 (Allison); No.2,938,378 (Canada, et al.); and No. 3,l 1 L028 (Lebow).

In the recent drive to reduce pollution in the atmosphere variousgovernmental agencies have decreed that the internal combustion enginein todays automobiles be built so as to minimize amounts of pollutants,such as hydrocarbons, carbon monoxide, oxides of nitrogen and the likeemitted to the atmosphere. It would be possible to achieve superioroperation of present engines if the engine could be adjusted as afunction of the power called for and the power to torque actually beingdeveloped. However, at present there exists no reasonably economicalmeans for constantly measuring the torque or power output of the engineso that the opcrating parameters of the engine may be continuallyadjusted in relation to the torque or power in such a way that overallperformance is optimized. For exam ple, it is known that there arecertain input fuel rates, certain fucl-to-air ratios, and certain sparkadvance settings which serve to maximize fuel burning within enginecylinders and/or maximize power output. It is further known that thesevarious engine conditions vary with automobile speed and with conditionsof acceleration, decleration, constant speed, etc., all of which can bedetermined for any particular automobile by mea suring the torque uponthe drive shaft thereof and its rpm, from which can be developedfeedback signals to provide control functions. The control functions, aslater discussed, can be a complex function derived from one or more ofthe measured operating characteristics. i.e., power, torque and rpm. NOtonly is it necessary in this particular use to provide torque and rpmvalues, but it is also necessary that the economics of the situation beconsidered and that such information be provided by apparatus which isboth accurate and inexpensive.

Accordingly, a principal object of the invention is to provide feedbacksignals indicative of power output and/or angular velocity and/or torqueof a powertransmitting shaft of an automobile driven by an internalcombustion engine or the like and to effect changes upon the operatingparameters of the engine in response to such signals to control theoutput power thereof.

A further object is to provide the foregoing in appa ratus employing alight modulation scheme whereby torque-related twist upon a shaft as aconsequence of power being transmitting by that shaft is converted toelectric signals indicative of torque, the angular veloc ity of theshaft being monitored also to provide electric signals and beingcombined in some circumstances to provide an indication of the powertransmitted by the shaft.

A further object is to provide means whereby either the angular velocityor the power transmitted by the shaft or the shaft torque can be used asa basis to provide input signals to the engine either in directrelationship to various values obtained or as complex functions, thesignals being fed to servo devices which, in turn, modify engineparameters thereby to control engine output.

A further object is to provide apparatus which can be used to monitorthe output power of an internal combustion engine to reduce thepollution caused by such engine.

It will be appreciated by persons skilled in this art that a torquemeasuring device has uses that go beyond that of controlling automobileengines. Such torque indicating means can be used, for example, tocontrol the outputs of electrical motors driving machinery to pro videconstant torque outputs, for example, or to control aircraft engines,large marine vessels and the like, or many, many other purposes.Broadly, therefore, still another object of the invention is to providea torquemeter wherein torque-related twist ofa power transmitting shaftis converted to changes or modulation in light transmitted or reflected(i.e., modulations of an optical signal), and such changes ormodulations in transmitted or reflected light serve as a measure of thetorque transmitted by the shaft.

A very important consideration in any apparatus employing a lightmodulation scheme of the type herein disclosed to derive torqueinformation is that very small angular changes as a result of twist uponthe shaft must be sensed. Thus, for example, in the case of automobiledrive shafts, torques are experienced from normal operating conditionsin the region of 50 ft.-lbs, to extremes as high as 500 ft.-lbs. Auseful torque measuring apparatus should reliably measure to within 10ft.-lbs. The amount of twist from one region axially displaced along theshaft from another region by, say twelve inches for a 10 ft.-lb. torqueis of the order of 0.0] degrees. In the typical 2-2 1: inch diameterautomobile shaft, this represents a change in the relative position atthe surface between points axially separated by approximately one footof approximately the order of 10 inches. Thus, any light device intendedto read changes in position in that shaft surface, as a consequence oftwist on the shaft, must be capable of sensing very, very smallmovement. A further object, therefore, of the present invention is tofurnish a light modulation device capable of sensing, accurately andconsistently, very small changes in shaft twist.

The ultimate use for apparatus of the type herein disclosed requiresthat such apparatus furnish accurate and reliable output signals, butthere are cost constraints, particularly in the automotive industry. Astill further and very important object of the invention is to providetorque-indicating apparatus which is capable of accurate to veryaccurate torque information on a consistent, reliable basis, butapparatus which is susceptible, nevertheless. of being produced bymassproduction methods to reduce production costs.

In order to convert very small shaft-surface position changes tomeaningful feedback signals it is further necessary to sense, quickly,small changes in the magnitude of reflected (or transmitted) opticalsignals. In one of the disclosed embodiments, two bands at one region ofthe shaft serve to furnish binary-type signals at such region, thebinary-type signals being combined with like signals generated atanother region. The duality of such signals allows very fast rates ofchanges of light pick up in the course of shaft rotation. As isexplained in greater detail hereinafter, the point of change in such anarrangement may be used as a switching mechanism to supply pulse-typesignals whose pulses have very fast rise and fall times thereby makingany feedback system employing such pulse signals very responsive. Thus,a further object of the invention is to provide modulation apparatus.pulse output signals or output signals in the form of a series ofpulses, initiation and termination of the individual pulses making upthe signal, in one embodiment, being a function of the change inradiation reflected by the rotating shaft and in another embodiment achange in light transmitted through a slotted flange arrangement fixedto the rotating shaft; and still another object is to provide in suchapparatus means for combining such binary-type signals with furtherbinary-type signals from some similar arrangement at another regionalong the shaft axially displaced from the first region to provide afurther output signal consisting of plurality of pulses, but in thislatter instance, providing combined pulses of constant pulse height butvaried pulse width.

The foregoing and still further objects are discussed in the detailedexplanation that follows and are particularly delineated in the appendedclaims.

The objects of the invention are attained, broadly, by apparatus formeasuring output torques transmitted by a rotating shaft that comprises,in combination: at least two pairs of optical channel means, each pairto pro vide a difference signal, means for combining the differencesignal from one pair with the difference signal from the other pair togive a train of electric pulses whose pulse width is determined by thecombined difference signals, said width being variable as a function ofthe torque transmitted by the shaft and interpretable to give anindication of said torque. In one form of the invention, each differencesignal is fed as an input to a threshold device, e.g., a Schmitttrigger, the output of each threshold device being connected as an inputto a logic gate to give the variable width pulses; in another form thedifference signals from the two pairs are connected as inputs to athreshold device the output of which is a variable width pulse train;and in still another form, gain is provided in the difference signalcircuit. The train of electric pulses may be fed through a time averagerto a multiplier where they can be combined with rpm readings to provideoutput power; the output power and/or torque and/or rpm can be convertedto complex polynomials by a function generator. The output of thefunction generator can, in turn. be connected to servo means forcontrolling an automobile engine or other prime mover, as laterdiscussed.

The invention will now be discussed with reference to the accompanyingdrawing, in which:

FIG. I represents, in block diagram form. an automobile having aninternal combustion engine drive or the like and having means formeasuring torque transmitted by a load bearing shaft as well as meansfor measuring shaft angular velocity;

HO. 2 shows a portion of the shaft to illustrate shafttwist sensingoptical means that includes two pairs of optical channels A-B and C-Dlocated at spaced regions along the shaft, each channel pair having twoside-by-side bands of alternate light absorbant and light reflectantareas;

FIG. 3 is a view taken upon the line 3-3 in FIG. 3 looking in thedirection of the arrows,

FIG. 4 is a view taken upon the line 4-4 in FIG. 3 looking in thedirection of the arrows;

FIG. 5A is a schematic representation, partially in block diagram form,of a scheme for converting light modulation from which torque andangular velocity signals are derived to electric signals;

FIG. 5B is a schematic of a modification of the arrangement of FIG. 5A;

FIG. 5C is a schematic of a further modification of the arrangement ofFIG. 5A;

FIG. 5D shows a pair of optical channels in two different positions, thechannels being operable in connection with the circuitry of FIG. 5C;

FIG. SE shows a single electric pulse developed by the circuitry of FIG.5C from signals obtained from the optical channels in FIG. 5D;

FIG. 5F shows a pair of pulses, similar to the single pulse in FIG. SEbut developed in circuitry obtained by slightly modifying the circuitryof FIG. 5C;

FIG. 5G shows a pulse train comprising two variable width pulses whichcan be obtained by feeding the pulses in FIG. 5F to appropriate elementsin the circuits of FIG. 5C;

FIG. 6A shows, on an enlarged scale, regions of the shaft having lightreflectant and light absorbant areas, in the form of two pairs of bands,from the light modulation stems;

FIG. 68, C, D, E and F show electric signals in the form of pulses whichcan be formed by the electric elements in FIG. 5A from the modulatedlight received from said areas and FIG. 6G show a variable-width pulsetrain that can be developed by the circuitry of FIG. SB;

FIG. 7 shows, in block diagram forms, a function generator adapted toprovide function in the form FIG. 8 shows a modification of the opticalaspects of the apparatus shown in FIG. 2;

FIG. 9A illustrates a pair of optical channels having a single band,rather than two bands as shown in FIG. 2, and having a particularrelationship between the length of each optical pick-up of the channelsand the width of the alternate light absorbant and light reflectantareas;

FIG. 9B shows a portion of the band at FIG. 9A and part of a pulsedeveloped by the arrangement of FIG. 9A;

FIG. I0 is a table showing the states assumed by the logic gate shown inFIGS. 5A and 5C when the gate is either an AND-gate. or an OR-gate. or aNAND-gate, or a NOR-gate as a function of the logic state of the systemcontaining the gate. the horizontal lines in the table representing nooutput from the respective logic element and the check marksrepresenting an output therefrom;

FIG. II represents the logic conditions for threshold devices related tothe pair of optical channels A-B and C-D and the various time intervalsthat these threshold devices operate at their respective logic states,the threshold devices thus represented being the Schmitt trigger devicesin the circuitry of FIGS. 5A and 5C;

FIG. I2 shows in block diagram form a method of interconnecting theSchmitt trigger devices of FIGS. 5A and SC to perform the logicfunctions of a logic gate without using the gate;

FIG. 13 shows in block diagram form a modification of theinterconnection scheme shown in FIG. 12;

FIG. 14 illustrates a modification of the apparatus shown in FIG. 2;

FIG. 15 is a partial view, on an enlarged scale, taken upon the lineI5-l5 in FIG. 14 and looking in the direction of the arrows FIG. 16illustrates a modification of the apparatus shown in FIG. 8',

FIG. I7 is a flow chart in block diagram form to describe theutiiization of the apparatus in FIG. 16, and

FIG. I8 is a flow chart that includes a control function generatorsimilar to that shown in FIG. 7 but including more functions.

Before going into structural details of the apparatus embodying thepresent inventive concept, there follows now a short discussion of whatis intended to be accomplished by it. The discussion is made primarilywith reference to a control unit of use in connection with an internalcombustion engine for an automobile, which is the preferred embodiment.The automobile is controlled by effecting changes, by use of suitableservo devices, in the amount of fuel delivered to the engine cylinders,the fucl-to-air ratio therein and/or the spark advance, and the controlsignals supplied to the servo devices comprise at least one of poweroutput, torque output and angular velocity (or complex functions derivedtherefrom) of a rotating shaft whose twist is a function of the poweroutput of the engine and power called by by the operator or by someregulation device such as a constant rpm control. The shaft in thediscussion immediately to follow is an automobile drive shaft. Readingsfrom which the control signals are derived typically are taken bycomparing angular twist between spaced regions along the shaft separatedaxially the order of six to twelve inches, and this is done by notingpositional changes of the shaft surface at one region relative to theother as a result of such torque-related twist. The shaft twist, whichis linear as a function of torque transmitted by the shaft, in such asituation is usually no more than about 0.1 of a degree in a typical twoinch diameter drive'shaft. Differential linear move ments of the shaftsurface as small as 10 inches must be detected to provide a usefulapparatus.

In the explanation to follow the invention is first discussed inconnection with an embodiment that employes two pairs of bands axiallydisplaced along a shaft whose twist is to-bemeasured. The bands areadapted to reflect and absorb radiation and thereby furnish binary-typelight signals as the shaft rotates. The light signals emanate from thebands in the form of light pulses and these light pulses form the basisfor electric signals from which torque (and other) information isderived. Each band pair may be. for example, a photo-etched metallyzedmaterial having an adhesive on the back thereof. However, as is laterexplained, other specific implementations of the broad basic concept canbe employed. Thus. although the immediately following explanationrelates to a situation wherein the light pulses are formed by lightbeing alternately reflected and absrobed by the respective bands, thepulses can be formed by a system in which light is alternatelytransmitted and blocked, for example.

By way of brief overall explanation, the necessary control functions arederived by measuring the torque or twist of the power transmitting shaftshown at 4 in FIGS. 1-4, measuring the angular velocity of that shaft,and combining these measurements to provide a complex control function,for example a polynomial in the transmitted powers, e.g., f p, P", orsome other function; or the torque and velocity measurements canthemselves provide useful control functions which are sent to a servosystem to actually carry out the adjustment of the engine. Thediscussion of this paragraph concerns means for obtaining torque values.Referring now to FIG. 2, the troque-determining means contains a firstpair of contiguous annular bands I00 secured around the shaft 4 (seeFIG. 3) at a first region and a second pair of contiguous annular bands10] secured amound the shaft at a second region, as shown. The regions,typically, are spaced six to twelve inches apart, and the amount ofdifferential movement at the shaft surface between the two regions as aresult of twist normally encountered is in the range of 10' to ID"inches for an autombile drive shaft. It should be quite apparent,therefore, that for meaningful control signals to be obtained, smalltwist movement of the shaft 4 must be detected. To accomplish this end,in the present invention radiant energy is directed to said spacedregions and sensed, and the magnitude of any changes in the radiation asthe shaft rotates in the direction indicated by the arrow H, due totwist, are detected. The radiant energy is obtained from the lightsource shown at 102 in FIG. 3, which may be a light bulb, a lightemitting diode or the like which delivers light energy directly orthrough light pipes (e.g., fiber optic elements which may range from0.0l to 0.00l inches in cross dimensions) l0 and 11 to the individualmembers 14 and 15 of the pair of bands 100. Each of the member strips I4and 15 is composed of alternate areas (such as the areas designated 32and 33 on the member I4) having differentlight reflecting and absorbingcharacteristics (i.e., the area 32 mostly absorbs light energy and thearea 33 mostly reflects it) immediately adjacent areas of the othermember (such as the areas designated 42 and 43 on the member 15) of thepair of bands having another characteristic. For example, as shown,light absorption areas 32 and 43 of the members 14 and I5, respectively,are immediately adjacent light reflection areas 42 and 33, respectively,of the members I5 and 14, respectively. The radiation source I02associated with the pair of bands I00 directs radiation either di rectlyor through the light pipes I0 and II upon each member of the pair ofbands I00. Radiation pick-up means is shown comprising a further pair oflight pipes I04 and I05; one end of the pipe 104 is positioned to pickup any light reflected from the member 14 and one end of other piper I05is positioned to pick up any light reflected from the other member 15.The light pipes 104 and 104 have light sensitive diodes or otherdetector devices D, or D respectively, having cross dimensionscomparable to the cross dimensions of the associated light pipes,secured to the end of the respective pipe opposite the pick-up endthereof, the devices D, and D each being operable to provide an electricsignal which varies as a function of the amplitude level of lighttransmitted thereto by the associated pipe. The

light pipes are secured in position by a structural element 8. Thesecond pair of bands 101 has elements similar to those just described inconnection with the pair of bands [00. Briefly, these include bandmembers 16 and 17, light pipes I04 and 105', detectors D and D and astructural element 9. The pick-up means associated with each piar ofbands provides a net output signal which acts as a control signal in theform of a pulse train of fixed-height pulses 38' and 39', as shown inFIGS. 6D and 6E. The pulse trains of the two pairs of bands are combinedto give the output product pulse train 40 shown in FIG. 6F. the width ofeach pulse member 40' thereof being related to the twist angle 6 (ortorque) of the shaft between the axially separated first and secondpairs of bands. In order that switch times of the order of llmicroseconds be obtained to furnish meaningful signals, the rise andfall times of pulses 38 39' and 40' must be quite steep. Also. theaccuracy of the initiation and termination of the pules 38' and 39' and.hence, 40' is determined in large measure by the angle designated ll!which is the slope of the net output difference primary signal from eachpair of diodes. The angle III is greater for the pair of diodes shownthan it would be for a single diode and is. further. affected by theindividual diode cross dimension and diode constants. i.e.. thelight-sensitive detectors D etc. each has an effective light-sensitiveregion or zone that is very small in cross dimension in the direction oftravel H. for example in FIG. 6A. of the areas 32, 33, 32', 33'therepast and each has light-to-electricenergy time response constantsthat are fast compared to the time of passage of the areas 32 etc. pasteach detector so that the rise and fall times (pulse transition times)of each pulse of said difference primary signal are much less than theduration of the pulse. Furthermore. the pulses 40'. as is evident fromthe discussion herein, are derived from two series difference signals(i.e., the difference primary signals 36 and 37 and the differencesignal obtained when the pulse trains 38 and 39 are combined) each ofwhich acts to determine the rise and fall times to the pulses 40'. thatis. to locate the times t i 1., hereinafter discussed with greatprecisron.

The first discussion herein contemplates the use of four opticalchannels which may be designated A, B. C and D. The light-modulatingelements consisting of the bands l4, I5, 16 and I7. and their associatedlight sensors and light pipes from the channels A. B, C and D.respectively. for present purposes. Each optical channel provides abinary-type message in the form of a chopped radiation beam; thus amessage from the channel A can be formed by alternately reflecting andabsorbing radiation from the areas of the band 14. as above discussed.to provide a binary message. The bi nary-type light message. in eachinstance. is converted to an electric signal by the associated lightsensitive de tcctor. The electric signal produced by the optical channelA is mixed with that of the optical channel B, similarly formed. to givea difference. primary signal 36 and that of optical channel C withoptical channel D to give another difference, primary signal 37. Thedifference. primary signals 36 and 37 in the embodiment of FIG. SA areconnected to respective Schmitt-trigger devices 22 and 23 which areregulated so that changes in polarity of their inputs (i.e.. thedifference. primary signals 36 and 37 respectively) causes the relevantSchmitt trigger to initiate and terminate a pulse sequentially therebyproducing a train of pulses (i.e.. 22 produces pulse train 38 and 23produces pulse train 39) -these two pulse trains are connected to alogic gate 26 to furnish the output pulse train 40 which, when furtherprocessed. provides a feedback control signal. In the embodiment of FIG.5B the electric signals are operated upon. in the manner mentioned inlater paragraphs, and then connected to a single Schmitt trigger device.In all situations, the output pulse train eventually generated is in theform of fixed height. but variable width. voltage pulses in the form ofa pulse train which is averaged for control purposes. There follows nowa detailed explanation of apparatus adapted to perform the foregoingfunctions.

The diodes D. and D as shown in FIG. 5A. are connected so that theiroutputs V, and V respectively, are subtracted and the net differencesignal is connected to a differential amplifier 20 to provide the netprimary output signal 36 shown in FIG. 63. that indicates a differencein the reflected radiation from the member bands 14 and I5. Two filters500, 501 are used to filter out undesirable noise. The output of thedifferential amplifier 20 is connected as an input to the pulsegenerator 22 which may be Schmitt trigger device. as shown. or aflip-flop or some other threshold device. In this way the net outputdifference signal acts as a control upon the Schmitt trigger 22 toswitch the Schmitt trigger from one state to another as the net outputdifference signal changes polarity, that is. at the zero crossings 1., tetc. in FIG. 6B. thereby to provide the train of fixed-height outputpulses 38' shown in Flg. 6D. The Schmitt trigger also produces pulseswith much shorter rise times than those primary signals gen erated (asshown in FIGS. 6B and 6C) directly from the output of the operationamplifier 20. Very short rise times permit very accurate deviceperformance. Similarly. the outputs V and V,, respectively of diodes D;and D are connected to a differential amplifier 21 which. in turn. actsas a control for the pulse generator 23 (also a Schmitt trigger in thedrawing). changes in polarity of the net output difference signal 37from the diodes D and D. again acting alternately to initiate andterminate pulses 39' of the train of fixed-height pulses 39 in FIG. 6E.The output of the pulse generators 22 and 23 are connected as the inputsto a logic gate 26 to give the output product train 40 (also termedfinal output pulse train" herein) in FIG. 6F. The product pulse train 40is a train of fixed height. variable width pulses made up of thevariable width pulses 40. as mentioned, the width of each pulse memberbeing related to the twist angle 0 of the shaft between the axiallyseparated first and second pair of bands and 10I. The logic gate 26 inthe arrangement shown in FIG. 5A performs a multiplier function.

FIG. 5C shows a more elaborate scheme for obtaining a pulse train from apair of optical channels. In order to measure 50 ft. lbs. of torque on adrive shaft of 0D. 2.4 inches and ID. of 2.0 inches and having anelastic modulus of 1.7 X 10 pounds/ft. it is necessry to sense atorque-related twist angle of approximately 3.0 X It) radians betweentwo points axially separated on the shaft by twelve inches. This wouldmean a pulsewidth modulation of approximately 3.6 X I0 inches. Ifchanges in pulse width are to be measured to one part in one thousand.then a pulse must be initiated and terminated by a surface rotary motionof the shaft of approximately It) inches. Hence. the widths of theabsorbing or reflecting areas 32. 33. 32'. 33' of the bands I and 101would have to be of the order of l0 inches wide. The fabrication of suchbands could lead to an inadmissable manufacturing cost. A superior meansfor generating both sharp and narrow pulses is described by the systemshown in FlG. C. To understand this system the details of the pulsegeneration technique are shown in HQ 5D. A pair of bands 697 containinga pair of optical channels, again designated channels A and 8, consistsof alternately reflecting and absorbing regions 702, 703, 705 and 704,as explained earlier. Photo-sensitive devices 700 and 701 sense theamount of light transmitted to them either by reflection (as shown here)or in an alternate embodiment using a transmitted signal. Thephoto-response of the device 700 is designated V and that of the device701 is designated V The photo-response is proportional to the degree ofillumination. The output of photocell 700 can be taken to be and thephotocell 70l where X denotes the variable position of the edge labeled706, and where X,X is the width, (i.e., the cross dimension of thelight-sensitive region of the solid-state light-sensitive detectorperpendicular to each passing boundary 706 at the instant of passage andparallel to the direction of said passage. as shown) photocells 700 and701. Both V and V are taken as 2 0 here. The response V is fed into anamplifier or attenuator with gain 14,; as shown at 800 in FIG. 5C andthe difference primary signal S =V g,,V can be fed into the operationalamplifier labeled A-l. Then the distance X that the boundary or edgedesignated 706 between an absorbing region 703 and a reflecting region702 (or between areas 704 and 705) must move to the left in order thatV, g,,V,,= 0, is X. (X g X /g +1). The larger g the smaller X Thecircuit can be such that a zero of V gV at X can initiate a pulse in theSchmitt trigger shown at 802 of FIG. 5C. As the boundary 706 moves pastX V -g,,V,, will remain negative until the next boundary labeled 707moves by the photocells. Next. consider the primary signal S g, V, Vobtained by feeding V, into an amplifier or attenuator 803. This signalis fed into the operational amplifier A-2, and g V V has a zero at Xgiven by X.' (X,,+g X /l+g.|)-Thc larger g, the nearer the boundarydenoted 706 approaches the left edge X of the photocells when anotherzero is fed to the Schmitt trigger 802 which must be able to sense achange in polarity of any signal fed into it. This is accomplished bymultiplying the outputs of A-] and A-2 (by a multiplier 208) before theyare put into 802. At point X. the pulse shown at 708 in FIG. 5E begun atX, is terminated. The pulse width in the space domain is Hence the pulsewidth is adjustable by varying the gains 3 and g Furthermore, as theboundary 706 sweeps past the photocells 700 and 701 (or light pipes 700and 701 to which the photocells are secured) a complete pulse isgenerated. Its width depends only on the gains g and 3,, and the width XX of the elements 700 and 701 and does not depend on the widths of theregions 702, 703, 704, 705.

A further advantage of this scheme is the great insensitivity of thepulse width X 'X, to fluctuations EV and 8V in the photocell output. Forexample the position X at which the pulse is initiated is changed to anew position )7. which differs from )t by Therefore, this difference maybe made a very small fraction of the net voltage fluctuation 5V, 8V In asimilar way the point X. may be stabilized resulting in a very accuratepulse width X X The remarks in the previous paragraph describe thegeneration of a pulse train from a pair of optical channels A and B. Asimilar means is used to generate a sec ond pulse train from a secondpair of channels C and D associated with a point on the powertransmitting shaft axially separted from A and B, as before discussed.The associated circuitry 801', 802', etc. performs the same functions as801, 802 etc. respectively, to generate primary signals S V g V and S g-V V Thus, a pulse similar to the pulse 708 can he formed and both canbe fed to the logic gate 26 to provide variable-width pulses like thepulses 40'. In the discussion to follow the condition that the thresholddevice associated with channels A and B has initiated a pulse isrepresented by a l and the condition that the pulse is terminated isrepresented by a 0. Similarly the presence of a pulse from channels Cand D is represented by a l and its absence by a 0. Then the fourpossible combined states are 00. Ol, 10, and ll. the first digit of thepair specifying the state of channels A-B and the second the state ofchannels C-D. The four logic elements appropriate to the joint states ofthe combined pairs of channels are described by the table in FIG. 10. Asin FIG. 6A pulses from the A-B pair are initiated at l t etc. andterminated at 1 etc. and pulses from the C-D channel pair are initiatedat 1 t etc. and terminated at I 1 2 etc. In FIG. H the state of thecombined A-B, C-D system is designated as time evolves from prior to toafter 1 Thus an AND gate gives an output between l and t between t andetc. As discussed in detail below such an AND-gate will produce a pulsetrain whose pulses are modulated in width according to the twist of theshaft. An OR-gate produces pulses in duration t,t 1 -1,. etc. ANAND-gate produces pulses in duration !,,1,'. 1 etc. A NOR-gate producespulses in duration r,,'-r,. r '-t etc. All of these pulses dependlinearly on the twist of the shaft. Hence the logic gate shown as 26 inFIG. 5A and FIG. 5C can be an AND. OR. NAND. or NOR gate. The functionof the logic gate 26 can be performed in still another way to provide apulse train in FIG. 50 whose time average is linearly dependent on thetwist of the shaft. In this situation the outputs of amplifiers A-l andA-2 are multiplied together; the product changing polarity whenever oneof the factors changes polarity. Similarly A-I' and A-2' are multipliedtogether. These product functions are then used as shown in FIG. 12 andFIG. 13. In FIG. I2 switches 850 and 851 direct successive primarysignal polarity changes to alternate Schmitt triggers 802 and 802',which produce pulse trains 852 and 853 whose pulses 854 and 855 arewidth modulated by the twist of the shaft. One or both of these pulsetrains 852 and 853 can be time averaged to produce a signal proportionalto the torque. In FIG. 13 a change in polarity of the product A-l X A 2always initiates a pulse from a single threshold device 860 if no pulseis already present and a change in polarity of the product A-l' X A-Z'always terminates a pulse if one is present. The resultant pulse train802 is made up of pulses 861 whose width is torque modulated and thetime average of this pulse train is proportional to the torque. It isapparent from the explanation herein that a wide variety ofconfigurations using switch and interconnection combinations is possiblethat will result in the signal whose time average depends linearly onthe torque.

In the circuitry of FIG. 58, elements which perform similar functions toelements in other circuits are given the same number designation as inthe other circuits. By using the circuitry in FIG. B the variable-widthpulse train shown at 4I in FIG. 6G can be generated. The outputs of theamplifiers and 21 in FIG. 5B are connected as inputs to a single Schmitttrigger 22'. The output of the Schmitt trigger 22' is in the form of thevariable-width pulses making up the pulse train 4I.

The discussion in the previous few paragraphs relates to a torque-meterthe output of which can, in and of itself, be used to furnish usefuldata and control functions for internal combustion engines or othertypes of prime movers. There follows in later paragraphs a fur therexplanation of the torque-meter, including comment upon the importanceof fast switching of the various pulsed outputs. There is, however, inthis paragraph a short description of the overall apparatus concernedwith the automobile control, with particular reference to FIG. I, wherethe torquemeter is designated 6. The output of the torque-meter 6 iscombined in a multiplier 7 with the output of an angular velocitydetermining means 5 to supply a power output signal which is connectedthrough a servo device 29 to operating parameters 2 which can be, asabove mentioned, means for controlling any or all offuel input,fuel-to-air ratio and spark advance. The inputs to the multiplier 7 aredesignated I8 and 19 and the output is designated I9. The output 19' canbe connected to the servo de vice 29 directly; or, as shown in FIG. I,it can be con nected through the control function generator shown at 320in FIG. 1 and in detail in FIG. 7, as later discussed,

and thence to the servo device 29. In FIG. 5A, the rpm indicator 5 isshown to include a monostable pulse generator 24, connected to receivean output from the dif ferential amplifier 2i, and a time averager 25,the latter being connected to the multiplier 7. The logic gate 26 isalso connected through a time averager, the time averager 27, to themultiplier 7. The circuitry of FIG. 5A shows the amplifier ZI in thetorque-meter circuitry, but it will be understood that the amplifier 21serves a dual function and is part ofthe rpm indicator 5, as well. Theoutputs of the torque-measuring means 6 and rpm indicator 5 can be fedthrough the multiplier, as mentioned, or they can be fed to servodevices 30 and 3|,

respectively, as shown, as control functions. Furthermore, the outputsof both can be connected to the respective servo mechanisms through thefunction generator 320, as indicated in FIG. 5A, the output of thefunction generator in each case being a complex polynomial of the inputfunction thereto. In any event, a processed signal from the functiongenerator operates to control some prime mover such as, for example, theinternal combustion engine designated 3 of an automo bile I in FIG. 1.

Referring now to FIG. 6A, there is shown an enlarged-scale view of aportion of the shaft 4, primarily to simplify the explanation as toFIGS. 63 -6F. The members I4, 15, I6, I7 in FIG. 6A are made up of areas32 that absorb light and adjacent areas 33 that refleet light, as beforementioned, the reflected radiation being picked up and transmitted tothe light sensitive detectors (e.g. diodes) before discussed by pick-uptubes 104 and I05 in the case of the strips I4 and I5 and by furtherpick-up tubes 104' and in the case of the strips 16 and I7. FIG. 6Ashows the first band I00 comprising the strips 14 and I5 and associatedlight pipes 104 and I05 as well as the second band IOI comprising thestrips I6 and I7 and their associated light pipes 104' and I05, whichmake up optical chan nels A, B. C and D, respectively. The sensorsassociated with the light pipes are not shown in FIG. 6A, but areimplied. The direction of the motion of the bands relative to thestationary optical elements I04, I05, 104 and 105' is given by the arrowH. The pulse trains shown in FIG. 6B-6F are formed when the circuitdescribed in SA is employed. As the boundary or edge shown as 34 betweenthe reflecting areas 33 and the absorbing areas 32 of the band I4 passesby the optical elements, the signal 36 (i.e., V,,) shown in FIG. 6B isgenerated by the channels A and B. This signal goes through zero at r,initiating a pulse 38' in FIG. 6D and terminating the pulse 38' at Thetime duration of the pulse 38' (i.e., r -r is determined by the width Wof the reflecting or absorbing areas of the particular band and theshaft rpm. The second band I01, containing the strips I6 and I7, ispositioned so that the boundary labeled 34 (corresponding to 34 in theunstressed shaft) would, if the shaft were unstressed fall at theposition numbered 35; however, a torque on the shaft moves this boundaryto the position of 34' shown in FIG. 6A. A signal 37, generated by thesecond band 101, is shown in FIG. 6C. if there had been no twist of ithe shaft, the zeros of primary signal 37 would have oc curred at timesI, and However, the shift of the boundary from 35 to 34' displaces thesezeros to t, and 1 The corresponding pulse 39 in FIG. 6E is also shifted.The signal out of an AND logic gate at 26 appears in FIG. 6F, the pulsetrain 40 being the resultant of inserted pulse trains 38 and 39 into theAND logic gate, as before mentioned. The width of the pulse 40 in thetime domain is r r, and is clearly altered by the twist of the shaftfrom the value r," it would have had in the zero torque case.

The relative displacement of two points on the surface of an automobiledrive shaft changes by approximately 10 4 inches for a torque in the I0ft.-lb. range to 10 inches in the 500 ft.-lb. range. Correspondingchanges in the pulse width of the output of the logic gate will occurwhich may he described in the time or space domain. If changes of notless than one part in a thousand are to be reliably measured, then thewidth W of the regions 32, 33, 32' and 33' must be approximately inches,as previously mentioned herein.

Still another method of generating a pulse modulated signal, asmentioned, is to feed both signals V,,-V,, and V -V into one Schmitttrigger adjusted to start and stop a uniform height pulse at successivechanges in the polarity in the signals V -V, and V --V,,, that is, theSchmitt trigger 22' (in FIG. SB, as above discussed) acts first on azero from V -V and next on a zero from V --V,,, next on a zero from V -Vand so forth. Using such a circuit, the pulse train 41 emitted by thispulse generator is that shown in FIG. 60. The pulse widths 4", I 4 etc.are themselves linearly related to the twist of the shaft so that a timeaverage of the pulse train 4l is directly related to the shaft torque.This means of pulse generation eliminates one Schmitt trigger and thelogic gate 26. The time average output coming from the pulse train 41 isused in a manner similar to the average of the pulse train 40.

Keeping the discussion in the previous paragraph in mind, a similarpulse generation scheme can be used when the gain devices 800, 803, 800,and 803 of FIG. SC are employed in a circuit slightly modified from thatshown in FIG. 5C. Here one Schmitt trigger is used and is appropriatelyinterconnected so that a polarity change in the signal from the firstpair of optical channels A initiates a pulse, if no pulse is on, and achange in polarity in the signal from the second pair of channels Bterminates the pulse; or the Schmitt trigger can be connected so thatthe roles of A and B are reversed. The pulse train so produced isautomatically pulsewidth modulated according to the twist of the shaftand no logic gate is required. These pulses also have all the advantagesof pulses generated using the scheme in FIG. 5C, ie. they are veryinsensitive to electrical instabilities.

In the illustrative example charted in FIG. 6B-6F, fixed-height pulses38' from the Schmitt trigger 22 are initiated at 1,, I 1 etc. andterminated at I I and fixedheight pulses 39 from the Schmitt trigger 23are initiated at t t etc. and terminated at t t etc. Thus, thefixed-height pulse trains 38 and 39 in FIGS. 6D and 6E delivered to anAND logic gate 26 are initiated when the primary signal pulses 36 and 37pass a zero point changing from negative to positive polarity and areterminated when the primary signal pulses 36 and 37 pass a zero pointchanging from positive to negative polarity. The output from an ANDlogic gate 26 is the product pulse train 40 in FIG. 6F. Since the pulsetrain 40 occurs for such a small element of time and is representativeof a situation in which any twist upon the shaft 4 is constant for theperiod of time in question, the pulses 40' making up the pulse train 40are of uniform width. However, as before explained, any changes in twistshow up in changes in pulse width of the pulses 40". these latterremarks apply also to the pulses making up the output pulse trains fromthe other circuit arrangements as well.

The explanation in this paragraph is concerned with a situation whereinthe shaft 4 is twisted some angle 6 from the unstressed condition. Inthe explanation, pulses 38'. 39' and 40' represent the pulses making upthe pulse trains 38. 39 and 40, respectively, as before. In thissituation the width of fixed height pulses 38 and 39 equals where T isthe period of one revolution of the shaft, r is the shaft radius. W isthe separation between the edge labeled 39' and the edge 34' in FIG. 6A,and W is the width of the absorbing and reflecting areas 32, 33, 32 and33, and

Pulse Area (i.e., the areas of the pulses 38' and 39) A8T= AW'T/Z'rrr,where A is height of the pulses 38' and 39 (which must be veryconstant). The voltage delivered by the time averager 27 is 8T NAW'TNAW' m=NA T 21rrT 21",

where N is the number of shaded (or reflecting) areas around the shaft.It will be observed that VT, is independent of shaft angular velocity.Continuing with the analysis where C is a constant depending on the zerostress alignment of bands and 101. The area of the fixed height,variable width pulses 40' equals The voltage out at some twist value 9is 0... A I21") [W'+C'+r0] Therefore, the averaged or integrated signalis linear as a function of twist of the shaft 4. Each pulse 40' musthave a rise time that is much less than the time required for an area32, 33 etc. to pass the detector light pipes.

As explained earlier, the embodiment shown in FIg. 5C will result invery sharply defined pulses whose widths are determined by the crossdimensions of the optical elements 104, I05, 104 and 105' (i.e., thewidth of the fibers and associated light-sensitive diodes; see prevousexplanation about width X -X in connection with FIG. 5D).

Previous mention has been made of the possibility of using a controlfunction generator 320 to receive the output of 19' from the multiplier7 and to process the signal in a way to provide control functions of thetype One such control function generator is shown in FIG. 7 wherein theline 19 is connected as an input to a block designated P the output ofwhich is fed to three multipliers 50. S1, and 52. A further input to themultiplier 50 is introduced to provide an output I and this output P inturn is introduced as an input to a multiplier 54, the other input towhich is the constant A and the output from which is A, P The output A,I

1. Apparatus that comprises, in combination, an automobile engine, amechanical member whose transmitted torque is related to the outputtorque of the engine, means measuring said torque and developing a timeaveraged electric output signal as a function of the torque, noisefilter means associated with the means measuring said torque andoperable to remove spurious mechanical and noise signals from the outputsignal, control function generator means connected to receive said timeaveraged output signal as a first input and operable to developtherefrom feedback control signals, and feedback control means connectedto receive the feedback control signals and operable to adjustautomatically the operating parameters of the engine, the operatingparameters being at least one of spark advance, fuel to air ratio, andfuel input to the engine.
 2. Apparatus as claimed in claim 1 in whichthe mechanical member is a shaft and in which the electric signaldeveloping means comprises an optical torque-meter associated with theshaft, said torque-meter comprising means for developing optically atrain of radiation pulses from which said electric signal is derived. 3.Apparatus aS claimed in claim 2 in which said torque-meter comprises afirst element disposed around said shaft and secured to the shaft at afirst region of the shaft, a second element disposed around said shaftand secured to the shaft at a second region axially displaced along theshaft from the first region, each element being composed of successivecontiguous areas of different optical characteristics having a sharplydefined boundary between adjacent areas, means for irradiating saidelements, whereby the radiation is chopped by said elements, and pick-upmeans positioned to receive the chopped radiation and produce acorresponding electrical pulse train output.
 4. Apparatus as claimed inclaim 3 in which the pick-up means comprises a radiation detector whoseeffective dimension in the direction of travel of said areas relative tothe pick-up means is small compared to the length of such areas in suchdirection and whose response time constants are sufficently fast thatthe rise and fall times of each electrical pulse are much less than thetime duration of the pulse.
 5. Apparatus as claimed in claim 4 in whichsaid torque-meter includes pulse generator means for generating a trainof rectangular-wave pulses which are initiated and terminated at timescorresponding to predetermined amplitude levels of said electricalpulses and which have duration proportional to the torque transmitted bysaid shaft, and means for time averaging the rectangular-wave pulses,the signal fed back to the control means being derived from thetime-averaged rectangular pulses, whereby the control is stabilized withrespect to electrical instabilities including changes in intensity ofthe radiation.
 6. Apparatus as claimed in claim 5 in which the secondelement is mounted on a coaxial sleeve secured to the shaft at thesecond region, the sleeve extending from the second region toward thefirst region so that the successive contiguous areas of the secondelement are in close proximity to the successive contiguous areas of thefirst element.
 7. Apparatus as claimed in claim 6 in which the noisefilter means comprises a third element, like the second element, mountedon the sleeve adjacent the second element, radiation source and pick-upmeans and pulse generator means associated with the second and thirdelements to provide a further train of rectangular-wave pulses, meansfor deriving a further time averaged output signal from said furthertrain of rectangular-wave pulses, the first input to the controlfunction generator being derived from the difference signal of the timeaveraged output signal and said further time averaged output signal. 8.Apparatus as claimed in claim 1 that includes means for determining theangular velocity of said shaft to provide therefrom a second inputsignal to the control function generator means, further means fordetermining the acceleration and deceleration of said shaft and adaptedto provide a third input signal to the control function generationmeans, the control function generator means being operable to developseparately or in combination from the first, second, and third inputsignals feedback control signals and to feed these signals to saidfeedback control means.
 9. Apparatus as claimed in claim 8 in which thecontrol function generator means includes memory means for storingconstants required in the generation of the control functions, memorymeans for storing the results of the intermediate computational steps inthe control function generation process, means for combining said first,second, and third input signals, multiplier means, means for addition,logic gate means and means for periodically generating adjusted controlfunctions in response to changes in the first, second, or third inputsignals.
 10. A torque-meter as claimed in claim 4 in which each saidelement is a flange having slots and teeth, attached to the shaft ataxially spaced regions along the shaft, the slotted flanges beingsubject to relative angular displacement as A result of torque-relatedtwist of the shaft, the slots and teeth of one element beingdeliberately aligned relative to the slots and the teeth of the otherelement to allow the twist of the shaft to be measured in eitherdirection.
 11. A torque-meter as claimed in claim 10 in which theradiation detector is a solid-state detector.
 12. A torque-meter asclaimed in claim 11 in which said cross dimension of the effective lightsensitive region of the solid-state detector is no greater than 0.01inches.
 13. A torque-meter as claimed in claim 11 in which said crossdimension of the effective light sensitive region of the solid-statedetector is small enough and said time constants are fast enough toallow determination of the twist angle to within 2% of that produced bythe maximum torque measured by the torque-meter.
 14. A torque-meter asclaimed in claim 11 in which said cross-dimension of the effective lightsensitive region of the solid-state detector is small enough and saidtime constants are fast enough to allow sensing of relative angularmovement between a boundary on one element and a boundary of the otherelement at least as small as 10 4 inches.
 15. Apparatus as claimed inclaim 1 in which the feedback control means includes servo devices. 16.Apparatus as claimed in claim 1 that includes means to establish a zerotorque reference level.
 17. Apparatus that comprises in combination, anautomobile engine, a rotatable mechanical member connected to transmittorque of the engine, the transmitted torque being related to the torqueoutput of the engine, means for measuring said torque over substantiallythe entire operating range of the engine and to provide atorque-dependent first electric output signal over said range, means fordetermining the engine rpm and conditions of acceleration anddeceleration over said range to provide an rpm-dependent second electricoutput signal and acceleration-deceleration dependent third electricoutput signal, means for removing mechanical noise from one or more ofsaid first, second, and third electric output signals to producecorresponding reduced noise electric output signals, control functiongenerator means connected to receive the reduced-noise electric outputsignals and operable to develop therefrom feedback signals, and meansconnected to receive said feedback signals and operable to control atleast one of the spark advance, fuel-to-air ratio, and fuel input, saidfeedback signals acting so as to regulate combustion within the enginecylinders in order to control the engine emissions to the atmosphere.18. A method of monitoring and controlling the performance of anautomobile that comprises, measuring the transmitted torque of arotatable mechanical member of the automobile, which torque bears adirect relationship to the automobile performance, thereby monitoringsaid performance, said measuring being made over the entire range oftorques normally encountered in the operation of the automobile,developing an electric signal as a function of said torque so measured,said electric signal being in the form of a time averaged output derivedfrom a train of pulses of variable time duration, the pulse timeduration being related to the shaft angular velocity and to said torquebut having time duration variations due to mechanical noise in the shaftin the torque measuring system compensating for the mechanical noise insaid train of pulses, the time averaged output being representative ofsaid torque and being fed as one input to a control function generatorwhich generates feedback control signals and supplies them tooperational controls of the automobile for the purpose of controllingthe performance of the automobile.
 19. Apparatus that comprises, incombination, an automobile combustion engine, a shaft connected totransmit torque of the engine, the transmitted torque being related tothe output torque of the engine, means measuring said torque anddeveloping an electric signal as a function of the torque, noise filtermeans associated with the means measuring said torque and operable toremove spurious mechanical noise signals, including spurious signalsintroduced by relative mechanical motion between the torque-transmittingshaft and other parts of the means measuring said torque, from thedeveloped electric signal, feedback control means operable to receivesaid electric signal and to adjust automatically the operatingparameters of the engine, the operating parameters being at least one ofspark advance, fuel-to-air ratio and fuel input to the engine. 20.Apparatus for controlling an automotive combustion engine, thatcomprises in combination means for developing an electric signal as afunction of the engine torque, means associated with the last-mentionedmeans for removing mechanical and noise signals from the developedelectric signal to produce an output signal, and feedback control meansresponsive to said output signal for adjusting automatically at leastone of the operating parameters of the engine.
 21. Apparatus as claimedin claim 20 in which said operating parameters comprises ignitiontiming, fuel-to-air ratio and fuel input to the engine.